It's the second time this month that Ruby on Rails has released updated versions for serious software flaws

Those using the Ruby on Rails Web application framework on their websites are being advised to update the software immediately after multiple new vulnerabilities were found. It's the second time this month that Rails has been patched because of serious flaws.

Ruby on Rails is an open-source Web application development framework that is widely used across the Internet on websites including Hulu, GroupOn, and Scribd.

One of the problems, CVE-2013-0156, lies in the parameter parsing code for Ruby on Rails, which would allow attackers to bypass authentication systems, perform SQL injection attacks or a denial-of-service attack against applications using Rails, according to an advisory on Tuesday. A SQL injection attack involves sending commands through a Web-based form to a website's backend database, which, if not protected properly, can return sensitive data.

The second issue, CVE-2013-0155, would allow an attacker to send unexpected database queries with the command "IS NULL" due to the way Active Record interprets parameters in combination with the way that JSON parameters are parsed, according to another writeup.

The writeup advised that this particular vulnerability is a variant of CVE-2012-2660 and CVE-2012-2694. "Even if you upgraded to address those issues, you must take action again," it said.

Four updated versions of Rails were released on Tuesday: 3.2.11, 3.1.10, 3.0.19, and 2.3.15, according to the Rails blog. "These releases contain two extremely critical security fixes so please update immediately," it advised.

It's the second time this month that Rails has been updated due to critical vulnerabilities. Rails versions 3.2.10, 3.1.9, and 3.0.18 were released on Jan. 2 to address CVE-2012-5664, a SQL injection vulnerability.

Rails apologized for releasing that patch so close to the holiday break, but said that "regrettably the exploit has already been publicly disclosed, and we don't feel we can delay the release."